Simple way to get the current value of a BehaviorSubject with rxjs5

Question

Previously in rxjs4 there was a method in the BehaviorSubject called: getValue() (doc here).

This method does not exist anymore in rxjs5.

So the only solution that I found to get the value of a BehaviorSubject was:

let value;
myBehaviorSubject.take(1).subscribe( (e) => value = e );

This code runs synchronously (I do not exactly understand why, but it does ...) and gets the value. It works, but it's not as clean as it could be if getValue() was present:

let value = myBehaviorSubject.getValue();

Why getValue() was removed in rxjs5 and what's the cleanest solution to this problem?

Keelykeen

The BehaviorSubject interface has been simplified - the getter is called just .value. – Unblushing

@arturgrzesiak I do not find any reference to this .value in the current doc: reactivex.io/rxjs/class/es6/… – Keelykeen

docs may be not up to date, but still it works. Take a look here as well: reactivex.io/rxjs/test-file/spec-js/subjects/… – Unblushing

Thanks for pointing this ! – Keelykeen

@Keelykeen was correct, this was never added to the documentation because it was never intended for consumer use. Anyone who upgrades to 6.5.0 will find that it is no longer working as it has been removed: github.com/ReactiveX/rxjs/issues/5085 – Bobcat

@JamieBarker this is incorrect, the discussion you linked is about of and not BehaviorSubject – Occlusion

Answer 1

As was pointed out by artur grzesiak in the comments, the BehaviorSubject interface was cleaned up, and the getter is now just myBehaviorSubject.value.

I just wanted to add this as an answer because I almost didn't read the comments to the original question, and would have missed the correct answer.

Universal

"I just wanted to add this as an answer because I almost didn't read the comments to the original question, and would have missed the correct answer." If the concern is that you're repeating the comment and it's not "your" answer, you can always community wiki it (though at 31 votes, I understand if the altruism wanes). – Cavorilievo

Seems to me if anyone isn't understanding how answers work it's Artur and not Tyson – Parasympathetic

That comment links to a breaking change about of, it has nothing to do with behavior subjects. – Tachyphylaxis

As of RxJS 6.5.4 (and looking forward to 7.x) both .value and .getValue() will be supported on BehaviorSubjects as a way to access the current value github.com/ReactiveX/rxjs/blob/6.x/src/internal/… – Guthrun

I submitted an edit to remove the comment about .value of BehaviorSubject being deprecated. As @AdrianBrand stated the github discussion is about of and not BehaviorSubject. .value is and will continue being supported in BehaviorSubject – Occlusion

Answer 2

Look at the source code to a behavior subject

https://github.com/ReactiveX/rxjs/blob/master/src/internal/BehaviorSubject.ts

It still has a getValue method, it has a value property that just calls getValue, it was there in RxJs5.

Here is a StackBlitz using RxJs5.

https://stackblitz.com/edit/typescript-gcbif4

All the comments talking about a breaking change in 6.5.0 are linking to comments about observables make with of not behavior subjects.

Tachyphylaxis

I have to say that rxjs it the best thing that ever happened to JavaScript. – Gothicize